Got an email from SETI@home about not dparticipating for a few years. Thought I'd give it a try again, so downloaded and installed the BOINC app, started BOINC Manager, selected SETI@home from the drop down menu in the "Choose a project" window, and then get the message "The URL you supplied is not that of a BOINC-based project". I DIDN'T supply the URL, your app did!

I logged on to the SETI web site, and cut-and-pasted the URL from the home page - same problem.

BOINC consists of two main parts: a client (can be called just boinc, or boinc-client) and BOINC Manager (boincmgr or boinc-manager). BOINC Manager is just a graphical user interface making it easier to control and command the BOINC client. The BOINC client does all the command decisions, contacts with projects, etc.

So it's the BOINC client that you need to give access to the internet, on TCP ports 80 and 443.
BOINC Manager and the BOINC client need separate access to each other on localhosy 127.0.0.1 through port 31416. This is not an internet access.Jord

Ancient Astronaut Theorists suggest that in many ways, you can be considered an alien conspiracy!

I only find BOINCManager, BOINC Installer & Uninstall BOINC on my machine. I have uninstalled the app and all associated files, logged on to SETI@home, and re-downloaded and installed the app. Problem still exists.